Prostate cancer is the most common site of cancer in men in the United States with over 230,000 men diagnosed with prostate cancer in 2004. This disease generally impacts older adults; 70% of all new cases occur in men greater than 65 years of age. Androgen ablation therapy is the standard treatment for advanced prostate cancer. For men with advanced stage disease, the median length of time on this treatment ranges from 2 to 5 years. The quality of life implications of this therapy have been well documented; however the impact of this treatment on cognitive functioning has not been fully elucidated. Cognitive functioning is vital for independence and productivity. Only recently have researchers published studies focusing on the cognitive impact of androgen ablation therapy. Although these studies have provided valuable preliminary results suggesting that androgen ablation may adversely affect memory, visuospatial abilities, psychomotor speed, and executive functioning, these studies are limited in number and have not produced consistent findings. These studies have focused on men who have been receiving androgen ablation therapy for only 6 to 12 months, however most men with advance stage prostate cancer will continue on androgen ablation for over 2 years. Additionally, these studies have not specifically focused on patients age 65 and older, the population most commonly afflicted with prostate cancer. This proposal seeks to address these gaps in the literature by conducting a comparison study that will compare the cognitive functioning of 75 men with late stage prostate cancer age 65 and older who have received androgen ablation therapy for 2 years to the cognitive functioning of 75 men with late stage prostate cancer who have not yet started androgen ablation therapy. The specific aims of this study are: 1. To determine the domains of cognitive impairment in men over the age of 65 who have received androgen ablation therapy for 2 years. 2. To determine the severity of cognitive impairment in men over the age of 65 who have received androgen ablation therapy for 2 years.